Spool valving xe2x80x9clagsxe2x80x9d take place in the volume chambers of a gerotor gear set. By way of example only, as one of the volume chambers becomes a maximum volume transition chamber, the spool valving will continue for one or two more degrees of rotation to communicate high pressure fluid into that volume chamber, the volume of which is not changing. The instantaneous result will be that the volume chamber has begun to shrink while still communicating with high pressure. Then the valving shuts off and the chamber shrinks further, and because of overlap in the valving, with no way to relieve pressure in the chamber, the fluid pressure will rise rapidly creating a pressure pulse or spike in that volume chamber. Such incorrect timing will result in a number of problems in the gerotor, each of which will have a further detrimental effect on volumetric efficiency and motor smoothness.
Therefore, the principal object of this invention is to provide a spool valve that is axially movable to cause the way that the oil is communicated between the inlet and outlet of the motor and the volume chambers of the motor to deal with a solution to the problems of valve timing through adjustability of the timing.
This and other objects will be apparent to those skilled in the art.
The motor of this invention has a small valve transmission shaft between gear set and spool valve, and a port plate between gear set and valve housing. The purpose of the port plate is partly to reduce the tilting angle of the valve transmission shaft, and partly to seal between the volume chambers of the gear set and the bore in the valve housing. The latter of the two occurs, because the bore in the port plate is smaller than the bore in the valve housing.
In the valve housing, a spool valve with a shorter length than the length of the bore is arranged. The spool valve is rotated together with the gear set, due to the valve transmission shaft, but is free to move axially. A support rod will keep the valve transmission shaft in position, and a spring acting upon the support rod will force the valve towards the push rod of the valve actuator.
The inlet and outlet ports are in connection with individual ring chambers on the spool valve, independently of the axial position of the valve. Through axial connections in the spool valve, oil is communicated from the ring chambers to oil passages in the valve housing, leading to each of the volume chambers. By rotating the spool valve, together with the gear set, oil is communicated between an inlet and an outlet of the motor and the volume chambers of the motor.